My 96 Tahoe needs a new motor, so I figured Id put a GenIII in it instead of a replacement 350. I know I need the following.

Motor mount adapter plates
engine
headers
wiring harness

Am I missing anything?
If I buy a Nelson Performance harness, would that be all I need to get the factory gauges to work? Do I need to run both computers? Ive heard that you did and that you didnt.
Any other small parts that I will need before I get started?
thanks